Arbuscular mycorrhizal fungi (AMF) form symbiotic associations with many crop plants and aid uptake of essential nutrients from the soil, particularly phosphorus, often leading to increases in plant biomass. Such associations will potentially increase in importance as more emphasis is placed on reducing fertiliser inputs in the future. AMF associations can also lead to secondary benefits including increased disease resistance and drought tolerance.

A current project involves screening an onion diversity set for growth and nutritional responses to AMF and a similar approach could be used for other crop species. So far, results have been encouraging. A strong onion-AMF interaction has been demonstrated in an initial screen of ten onion lines from the diversity set. All the AMF species tested had significant growth effects on the onions and there were large differences in these growth responses between different lines. Differences in the levels of macro- and micro-nutrients were also observed between control and AMF-inoculated plants. The next step will be to identify genetic markers associated with response to AMF and hence accelerate breeding programs for sustainability traits in onion.